In Cork, residents have already been told to avoid tap water after the waterworks were flooded.

Environment Minister John Gormley said was a "we have been told this is a once-in-800 years event."

The rising flood waters now cover tens of thousands of acres of land and insurance companies say they expect the floods to cost in excess of €100m ($148m).

In Cork, parts of the city are under three feet of water after the River Lee burst its banks and flooded Grand Parade and Washington Street and large parts of the city center.

Emergency room access at Mercy Hospital was cut off after a nearby wall was toppled by the rising floodwaters.

The campus of the famed University College Cork was also under water.

In Bantry, the town was cut off and callers to RTE radio appealed for help. One woman in Kinsale said she needed help to remove a tree from her roof and a disabled woman in Sunday's Well in Cork City called in to say she had no way out of her house.

The Irish weather service Met Eireann said the misery looks set to continue with more heavy rain and gales over the weekend.

800 year floods: Cars submerged in Cork after the River Lee burst its banks and flooded the city center